Before I started Zen practice, I intuitively assumed that the ego was a solid, irreducible entity that existed inside of me and looked out on a separate, external world of objects. Meditation, and labeling thoughts in particular, has begun to erode that view of mine. The analogy I like to use is one relating to birth. When a women is experiencing labor contractions, her cervix begins to thin to allow the baby to pass through the birth canal. This process is called effacing. And that's how I see Zen practice--but instead of thinning the cervix, we're thinning the barriers of the ego.
The longer we sit and examine the nature of experience and this so-called 'I,' the less solid our sense of self becomes. In fact, no matter how hard we try to find the center of our being, to isolate some irreducible core, the more it eludes us. It's like the picture above--an endless hallway of shifting selves. In Buddhism, this is explained by the teachings of anatman and shunyata. According to the principles of no-self and emptiness, we lack the very thing that we falsely imbue ourselves with--an essence.
That's where labeling thoughts come in. The more we confront our ego-driven habits and impulses, label and acknowledge them, the more aware we are of them, and conversely, the less powerful they become. The barriers of this this false construct, the ego, begin to thin, to efface so to speak, and we experience moments of freedom. Freedom from greed, anger, jealousy, ill-will.
From my own experience, I have found labeling thoughts vital, in that it forces us to confront our own narcissism and eventually realize that the ego we are endlessly serving to protect and appease, is not a fixed, solid entity at all.
Like the thinning of the cervix, the effacing ego gives birth--to our true nature. Our true face before our parents were born.
Or so I'm told...
Image borrowed from Creative Commons flickr user: !unite.